The present invention relates to a device for turning panels, especially for turning wooden panels on panel saw machines.
Panel saw machines of known type are used to cut panels that vary both in width and length, usually placed one over the other in normally large stacks whose dimensions depend on the size of the panels made by the panel forming machines.
Panel saw machines, in their minimum standard configurations with a single cutting line to which we shall refer in this specification, basically comprise: a horizontal worktable to support the stacks of panels to be cut; a unit for picking up the panels and feeding them, along an axis X (horizontal), towards the end of the table opposite the stack loading end; a cutting device operative on the part of the panel stack at the end where the supporting table is located.
More specifically, the pickup unit comprises a beam equipped with a plurality of pickup elements, for example of the gripper type, located side by side in a direction Y at right angles to the direction of forward or backward feed. The pickup elements act on the rear edge of the panels to be cut and may carry and/or hold the panels in position while they are being cut or moved backwards and forwards on the worktable.
The cutting device is mounted on a carriage that moves in both directions along the axis Y transversal to the panel feed axis X so as to cut right through all the panels if these are stacked or through only one if a single panel is being processed.
Usually, after the panels have been fed to the cutting line, they are trimmed and then, when necessary, cut one or more times according to a predetermined pattern.
After the feeding step, if the panels have to be cut first along a direction parallel to the feed direction corresponding to the axis X, the panel stack or the single panel has to be turned through a right angle so that it can be fed to the cutting device in a position appropriate for the programmed pattern.
To facilitate the work of the operators who have to turn the panels downstream of the cutting device, devices such as the one described in patent EP-1057599 have been devised. These devices basically comprise an element for holding down at least one panel being processed and means for turning the panel about the hold-down element.
More specifically, the hold-down element is located in the vicinity of the worktable in such a way as to form a pivot in a preset area of the panel and the means for turning the panel about the pivot facilitate panel movement to change the position of the panel relative to the cutting device.
These turning devices, however, have a complex structure including numerous components such as pusher elements associated with the pickup units.
On account of their complexity, the cost of these devices and hence of the machines they are mounted on tend to be quite high.
In particular, when the panel turning means operate in combination with the pickup units, the latter have to be mobile at least transversely along the aforementioned beam, which means that additional components and technology are required, thus further increasing costs.
Prior art turning devices also include rotating platform type devices consisting of a large turntable located in the middle of the worktable and designed to turn the panels positioned on it. On account of their size and position, however, devices of this kind make further processing of the panels impossible since no room is left on the panel saw machine to cut the sub-panels transversely again.
In particular, since the turntable with the stack of panels on it is located in the middle of the worktable, it is impossible for the operator to move the sub-panels back onto the worktable from downstream of the cutting device since there is not enough room on the worktable itself. Furthermore, panels may be stacked on the turntable but are not secured to each other, with the risk of the stack falling apart.